Spark plug anti-foulant

ABSTRACT

A method of reducing spark plug fouling in spark ignition engines fueled with organomanganese containing gasoline is described. The method features the use in gasoline of a spark plug anti-fouling amount of an organic molybdenum compound. Molybdenum naphthenate is an example of a useful anti-foulant compound.

United States Patent [191 Hnizda 1*Aug. 28, 1973 [54] SPARK PLUG ANTI-FQULANT 2,881,062 I 4/1959 IBishop 44/69 3,003,859 10 l96l h l... [75] Inventor: \gilncegt allilliizda, Huntington 348179 12%969 lf fif [73] Assignee: Ethyl Corporation, Richmond, Va.

Primary ExaminerDaniel E. Wyman l 1 Notice g of g 2 Assistant Examiner-W. J. Shine fi g izggig Attorney-Donald L. Johnson. Daniel T. Szura et al.

[22] Filed: July 1, 1971 211 A 1. No.: 158 983 pp 57 ABSTRACT Related US. Application Data [63] fggg xz zg i zr 785301 A method of reducing spark plug fouling in spark ignition engines fueled with organomanganese containing [52] U 8 Cl 252/386 gasoline is described. The method features the use in [SI] 6 3/00 gasoline of a spark plug anti-fouling amount of an or- [58] Field of Search 44/66, 68;252/386 Molybdenum naphthenate is an example of a useful References Cited anti-foulant compound.

UNITED STATES PATENTS 3/1956 Thomas 44/68 X 13 Claims, No Drawings 1. SPARK PLUG ANTI-FOUIJANT CROSS REFERENCE TO RELATED APPLICATION This application is a Continuation-in-P art o'f'S er. No. 785,801, filed December 20, 1968' noWU.S." Pat. No. 3,615,293.

BACKGROUND OF THE INVENTION The invention is directed to improving theoperation of an internal combustion engine fueled with-gasoline containing organomanganese antiknock.- The'ir'rlprovement lies in the addition to saidfuel "of an organic mo lybdenum compound.

Cyclopentadienyl manganese tncarbonyls'are knownto be effectivegasolin'e 'ant'iknock'agents, cf. U. S. Pat.

No. 3,127,351, issued Mar. 31, 1964. It is also known that in using 'fuels containingthese' manganese comsuch deposits on the spar'k'plu'g is commonlyrefe'rred to as spark plug fouling. Spark-plug'foulingreduces the" cfficiency of engine operation. Non-metallic phos phates and xanthates'have'been' disclosed as useful ad'- ditives to reduce spark 'plu'g fouling 'tenden'ciesofsuch manganese containing fuels. (Cf. NewAnti knock-For' Gasoline," A. A. Gureeva, p. 5862, Ts. N;I. l.T.'E. Pe

troleumgas, Moscow' (1963); and RuSSiarVPit'. No.

The present invention-provide'sanovel metallic'addi SUMMARY'OF' THE'I'INVENTION" A method of reducing spark plug foulirig 'ininternal combustion engines fueled with giisoline characterized by being substantially free'oftetrahydrocarbyl lead ntiknock agents containing an organo'man'ganeseantiknock, by adding to said gasoline priorto' ignition 'an organic molybdenum compoundfih'e gasoline compositions containing the organo manganesecompound and the molybdenum spark'plug anti-foulant.-

DESCRIPTION or THE PREFERRED EMBODIMENT An embodiment of thisinventio'n is a method of reducing spark plug fouling in internal combustionen gines when burning gasoline which is "substantially'free of tetrahydrocarbyl lead antiknock's and contains a' manganese antiknock compound by a dding to said gas oline prior to burning a spark'plug 'anti foulant amount of a molybdenum compound. Ina preferred-embodb ment the manganeseantiknockis a cyclopentadienyl manganese tricarbdriyl wherein said cyclopent'adie'nyl group has up to' I 3 carbon atoms and said-molybdenum wherein X, X, X and X are independently selected from O and S and R and R are independently selected from hydrocarbon alkyl and aryl groups having from I to about 30 carbon atoms.

c. hydrocarbon carboxylic acids having from 5 to about 24 carbon atoms, and

d. naphthenic acids. An amount of the manganese antiknock and the molybdenum compound sufficient to provide an atomic ratio of manganesezmolybdenum (MnzMo) of about 1:1 to

about 110.05 is also preferred; molybdenum naphthenate is "an especially preferred molybdenum additive. These and other embodiments of the present invention will be made clear by the description which follows.

Any gasoline suitable for use in internal combustion engines may be used in the practice of this invention provided it is substantially free of tetrahydrocarbyl lead compounds such as tetraethyl lead and the like. By gasoline is meant a hydrocarbon or blend of hydrocarbons boiling in the range from about25 to about 250 C whichoccur naturallyin petroleum as well as suitable hydrocarbons manufactured from' petroleum, for example, by thermal of catalytic cracking, polymerizing, reforming, and the like. Typical gasolines are listed in Table I.

TAIILIC I.IIYI)ROCARIION COMPOSITION ()1 BASIC Aspointed out above, the gasolines are characterized as beingsubstantially free of tetrahydrocarbyl antiknock compounds. In' the course of handling gasolines in refinery operations and the like, base gasolines may pick up trace amounts of tetrahydrocarbyl antiknock compounds. These trace amounts are generally less than about 0.1 grams of Pb/gallon as the tetrahydrocarbyl lead compound. Thus the term substantially free of tetrahydrocarbyl lead antiknock agents, include such'base gasolines including such trace amounts of lead.

Manganese compounds which are useful as antiknock agents in gasoline compositions of the present invention are cyclopentadienyl manganese tricarbonyls having the formula RMn(CO) wherein R" is a cyclopentadienyl hydrocarbon radical having'from 5 to 13 carbon atoms. Useful compounds are exemplified by cyclopentadienyl manganese tricarbonyl, iridenylmanganese tricarbonyl, diethylcyclopentadienyl manganese tricarbonyl, 4-tert-butylindenyl manganese tricarbonyl and isopropylcyclopentadienyl manganese tricarbonyl. U. S. Pat. No. 3,167,351 issued Mar. 31, 1964, contains an extensive disclosure of the type of manganese compounds which are useful. This disclosure of compounds is incorporated by reference.

(Methylcyclopentadienyl)manganese tricarbonyl is an especially effective antiknock agent. The concentration of the manganese tricarbonyl in the gasoline may be varied. Concentrations from 0.5 to about 6.0 grams of manganese per gallon as a cyclopentadienyl manganese tricarbonyl are useful.

Molybdenum compounds which are useful in the present invention are organic, gasoline soluble or gasoline dispcrsible compounds. They include molybdenum salts and chelates. Organic molybdenum compounds which are gasoline soluble are preferred; by gasoline soluble is meant sufficient solubility in gasoline to effect spark plug antifouling as herein described.

One class of useful organic molybdenum compounds are molybdenum chelates. These chelates are coordination compounds in which a central molybdenum atom is joined to two or more atoms of one or more other molecules or ions (called ligands) so that one or more heterocyclic rings are formed with the central molybdenum atom as part of each ring. Examples of these compounds are chelate complexes of molybdenum with acetylacetone, N-nitrosophenylhydroxylamine, dimethylglyoxime, ethylenediamine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, 8- hydroxyquinoline, benzoylacetone, 2,4-per1tanediene, 4-methylamino-2-buten-2ol, and similar chelating agents.

Another class of useful organic compounds are the molybdenum phenates. These are salts of molybdenum and phenol or substituted phenols, and especially C -C alkylphenols. The simplest member of this class of compounds is molybdenum phenate; representative formula for molybdenum phenates are Mo(O-Ph) and wherein x is an integer from 2-6 inclusive and Ph is the phenyl or substituted phenyl group. Salts of molybdenum and the following phenols are useful 4-methylphenol 4-octadecylphenol 4-oleylphenol 4-(2-ethyl-n-hexyl)phenol 2,6-dimethylphenol 2,4,6trimethylphenol o-chlorophenol 2-dodecylphenol 2,4-didodecylphenol n-nonylphenol Z-tert-butylphenol 3-nitrophenol and the like.

An especially useful type of a molybdenum phenate is that derived from a commercial mixture of alkylated phenols. Commercial alkylation of phenols generally is accomplished by treating the phenol with an olefin or a mixture of olefins in the presence of an alkylating agent. This commercial alkylation ordinarily produces a mixture of various alkyl phenols. For example, if a phenol is alkylated with a C olefin, the product will contain monononylphenols, dinonylphenols, and trinonylphenols. Likewise, if a mixture of C C C olefins is used in the alkylation, a mixture of various C C and C alkylated phenols is obtained. Molybdenum salts of these commercial mixtures of alkylated phenols wherein the alkyl groups have from 3 to about 18 carbon atoms are also useful in the present invention.

Another class of useful compounds are molybdenum salts of hydrocarbon substituted phosphoric acids; these include the thiophosphoric acids. These phosphoric acids are represented by the following formula wherein X, X', X? and X can be 0 and/or S and R and R,, are hydrocarbyl groups. Hydrocarbyl groups are hydrocarbon alkyl and a ry] groups; hydrocarbyl groups having from I to about 30 carbon atoms are useful. Examples of molybdenum salts of acids of formula I are S-molybdcnum-0,0-dimethylphosphorothioate O-molybdenum-O',O"-dioctylphosphorothioate molybdenum diphenylphosphate molybdenum dicresylphosphate S-molybdenum-O,S-didecylphosphorodithioate molybdenum diamylphosphorotetrathioate O-molybdenum-S,S-di-tert-butylphosphorotrithioate O-molybdenum-O',O"-dixylylphosphorothioate S-molybdenum-S',S"-di-4-ethylphenylphosphorotrithioate molybdenum dioctadecylphosphorotetrathioate molybdenum cresylphenylphosphate O-molybdenum-O',O"-dinaphthylphosphorothioate S-molybdenum-O,O"-diisopropylphosphorothioate molybdenum dibenzylphosphate and the like. Salts of dithiophosphoric acids where two of X, X, X and X in Formula I are S are preferred. Examples of preferred salts are S-molybdenum-0,0'-dimethylphosphorodithioate S-molybdenum-0,0'- dicresylphosphorodithioate S-molybdenum-0,0-di-4-dodecylphenylphosphorodithioate S-molybdenum-0,0'-dibenzylphosphorodithioate S-molybdenum-0,0-dilaurylphosphorodithioate S-molybdenum-0,0'-di-2-ethylhexylphosphorodithioate S-molybdenum-0,0-diisobutylphosphorodithioate S-molybdenum-0,0'-methylphenylphosphorodithioate S-molybdenum-0,0-dicyclohexylphosphorodithioate S-molybdenum-O,S-diamylphosphorodithioate v I S-molybdenum-O,S'-diindenylphosphorodithioate S-molybdenum-O,S-dixylylphosphorodithioate S-molybdenum-O,S-dioctadecylphosphorodithioate S-molybdenum-O,S-diundecylphosphorodithioate O-molybdenum-S,S'-diheptylphosphorodithioate O-molybdenum-S,S'-di-2,o-tert-butylphenylphosphorodithioate O-molybdenum-S,S-diethylphosphorodithioate O-molybdenum-S,S'-ditetradecylphosphorodithioate O-molybdenum-O',S-diacetylphosphorodithioate O-molybdenum-O',S-di-2,4-didodecylphenylphosphorodithioate O-molybdenum-O,S-dioctadecylphosphorodithioate O-molybdenum-0',S-dihexylphosphorodithioate and the like. Another class of useful compounds are the salts of hydrocarbon carboxylic acids having from 5 to about 24 carbon atoms. Examples of suitable salts of this type are molybdenum pentanoate, molybdenum oleate, molybdenum linoleate, molybdenum adipate, molybdenum-2-ethylhexanoate, molybdenum benzoate, molybdenum tetradecanoate, molybdenum orthopthalate, molybdenum-4-dodecylbenzoate, molybdenum stearate, molybdenum laurate and the like. Molybdenum salts of mixtures of fatty acids obtained from natural products such as olive oil, babassu oil, tall oil, cottonseed oil, tallow, coconut oil and the like are also useful. More preferred molybdenum compounds of this type are the salts of alicyclic carboxylic acids. Specific examples of useful molybdenum salts of alicyclic carboxylic acids are molybdenum cyclopentanecarboxylate, molybdenum cyclopentylacetate, molybdenum 3-methylcyclopentylacetate, molybdenum camphonanate, molybdenum cyclohexanecarboxylate, molybdenum 3-dodecylcyclohexanecarboxylate, molybdenum 2,6-di-cyclohexylcyclohexane carboxylate, molybdenum v 2-cyc1ohexyl-4,6-dipehtyl-4-methylcyclohexanecarboxylate, molybdenum 4-methylcyclohexanecarboxylate, molybdenum 2,2,6-trimethylcyclohexane carboxylate and the like.

An especiallypreferred class of organic molybdenum salts are salts of the so-called naphthenic acids. The term naphthenic acids is applied to a mixture of carboxylic acids obtained from the alkali washes of petroleum. These acids are complex mixtures of normal and branched aliphatic acids, alkyl derivatives of cyclopentane and cyclohexane carboxylic acids and cyclopentyl and cyclohexyl derivatives of aliphatic acids. The alicyclic carboxylic acids appear to be the major constituents of these mixtures. The composition of these naphthenic acids will vary depending on factors suchas the source of petroleum, the refining procedure, etc. A more detailed discussion of these naphthenic acids is presented in Chemical Technology of Petroleum, William A. Gruse and Donald R. Stevens, 3rd edition, pages 65-67, 1960, McGraw-Hill Publishing Company; and is incorporated by reference.

For commercial use, the crude naphthenic acid mixture obtained in the alkali extract is generally refined to remove unsaponifiable material. Molybdenum salts of either the crude naphthenicacid mixture orof the refined naphthenic acid mixture are useful in the present invention. The molybdenum saltsof the refined naphthenic acids are especially preferred; the term molybdenum naphthenate" will be used herein to describe these especially preferred salts,

The amount of organic molybdenum compounds described above which is added to the organomanganese containing fuel may be varied. In general, sufficient organic molybdenum compound is added to the fuel so that the atomic ratio of manganese (Mn): molybdenum (M0) is from about 1:1 to about 12005.

The fuels used in the present invention can be prepared by adding the required manganese and molybdenum compounds directly to the gasoline which is substantially free of tetrahydrocarbyl lead antiknock agents. No special preparation appears to be required; con ventional blending equipment can be used. If desired, the manganese and molybdenum compounds can be pre-mixed to form a concentrate, commonly called an additive fluid, for addition to the gasoline. These concentrates containing the molybdenum and manganese compounds are another embodiment of this invention.

Other gasoline additives such as dyes, antioxidants such as alkylated phenols, diamines, phosphites and the like, metal deactivators such as N,Ni-disalicylidene- 1,2-diaminopropane and the like, carburetor detergents such as fatty acid amides, anti-icers, methylcarbitol and the like, corrosion inhibitors such as linoleic acid dimer and the like can also be present in the gasoline compositions of the present invention; these additives can, if desired, also be added as concentrate mixes or additive fluids to the gasoline composition.

The following examples illustrate fuels which are useful in the present invention. The molybdenum naphthenate used in Examples 1-5 is a commercial product, Nuodex Molybdenum Naphthenate, which is reported by the manufacturer to contain 5 percent by weight of molybdenum. The additives in the Examples may also be added as the aforesaid concentrates.

Example 1 To isooctane was added 2.0 grams per gallon of manganese as (methylcyclopentadienyl)manganese tricarbonyl and 0.25 grams per gallon of molybdenum as molybdenum naphthenate.

The MnzMo atomic ratio of this fuel is about 11007.

Example 2 An additional 0.25 grams per gallon of molybdenum as molybdenum naphthenate was added to the Example l fuel composition;

The Mn:Mo atomic ratio of this fuel is about 120.14.

Example 3 To base gasoline C is added 2.0 grams per gallon of manganese as (methylcyclopentadienyl)manganese tricarbonyl and 3.6 grams per gallon of molybdenum as molybdenum naphthenate.

The MnzMo atomic'ratio of this fuel is about 1:1.

Example 4 Example 5 To base gasoline G is added 3.0 grams per gallon of manganese as tert-butylindenylmanganesetricarbonyl and 0.27 grams per gallon of molybdenum as molybdenum naphthenate.

The MnzMo. atomic ratio of this fuel is about 120.05.

Example 6 To isooctane was added 2.0 grams per gallon of manganese as (methylcyclopentadienyl)manganese tricarbonyl and 0.25 grams per gallon of molybdenum as a commercial molybdenum alkyldithiophosphate (alkylphosphorodithioate) available under the name Molyvan L, Molyvan L is reported by the manu facturer to contain 7.5 percent molybdenum, by

weight.

The MnzMo atomic ratio of this fuel composition is about 120.07.

Example 7 To base gasoline A is added 0.8 grams pergallon of manganese ascyclopentadienylmanganese tricarbonyl and 0.79 grams per gallon of molybdenum as molybdenum/acetylacetone chelate.

The Mn:Mo atomic ratio of this fuel is about 11055.

Example 8 To base gasoline B is added 6.0 grams per gallon of manganese as ethylcyclopentadienylmanganese tricarbonyl and 0.54 grams per gallon of molybdenum as molybdenum/8-hydroxyquinoline chelate.

The MnzMo atomic ratio of this fuel is about 1:0.05.

Example 9 To base gasoline C is added 5.0 grams per gallon of manganese as indenylmanganese tricarbonyl and 6.3

grams per gallon of molybdenum as molybdenum/1,3- propylene diamine chelate.

The MnzMo atomic ratio of this fuel is about 1207 Example 10 To base gasoline D is added 4.0 grams per gallon of manganese as cyclopentadienylmanganese tricarbonyl and 2.1 grams per gallon of molybdenum as molybdenum benzoate.

The Mn:Mo atomic ratio of this fuel is about 1:03.

Example 1 1 To base gasoline E is added 3.0 grams per gallon of manganese as ethylcyclopentadienylmanganese tricarbonyl and 5.4 grams per gallon of molybdenum as molybdenum diphenyl hydrogen phosphate.

The MnzMo atomic ratio of this fuel is about 1:1.

Example 12 To base gasoline F is added 2.0 grams per gallon of manganese as (isopropylcyclopentadienyl)manganese tricarbonyl and 1.4 grams per gallon of molybdenum as molybdenum phenate.

The MnzMo atomic ratio of this fuel is about 1:04.

Example 13 To base gasoline G is added 1.0 grams per gallon of manganese as (ethylcyclopentadienyl)manganese tricarbonyl and 1.0 grams per gallon of molybdenum as molybdenum 4-octadecylphenate.

The MnzMo atomic ratio of this fuel is about 1:0.6.

Example 14 To base gasoline A is added 0.5 grams per gallon of manganese as (methylcyclopentadienyl)manganese tricarbonyl and 0.2 grams per gallon of molybdenum as molybdenum 2,4-diisopropylphenate.

The MnzMo atomic ratio of this fuel is about 1:02.

Example 15 To base gasoline B is added 0.6 grams per gallon of manganese as indenylmanganese tricarbonyl and 0.11 grams per gallon of molybdenum as O- molybdenum,0,O"-ditriacontylphosphorothioate.

The MnzMo atomic ratio of this fuel is about 1:0.1.

Example 16 To base gasoline C is added 2.5 grams per gallon of manganese as (dimethylcyclopentadienyl)manganese tricarbonyl and 4.0 grams per gallon of molybdenum as S-molybdenum-0,0-di-tertbutylphosphorodithioate.

The Mn:Mo atomic ratio of this fuel is about 1:09.

Example 1 7 To base gasoline D is added 3.5 grams per gallon of manganese as (2-methylindenyl)manganese tricarbonyl and 5.0 grams per gallon of molybdenum as S- molybdenum-0,8'-dimethylphosphorotrithioate.

The Mn:Mo atomic ratio of this fuel is about 1:0.8.

Example 18 To base gasoline E is added 4.5 grams per gallon of manganese as (diisopropylcyclopentadienyl)manganese tricarbonyl and 1.2 grams per gallon of molybdenum as molybdenum didocylphosphorotetrathioate.

The MnzMo atomic ratio of this fuel is about 110.15.

Example 19 To base gasoline F is added 5.5 grams per gallon of manganese as (hexylcyclopentadienyl)manganese tricarbonyl and 2.5 grams per gallon of molybdenum as molybdenum cyclopentane carboxylate.

The MnzMo atomic ratio of this fuel is about 1:0.25.

Example 20 To base gasoline G is added 1.5 grams per gallon of manganese as fluorenylmanganese tricarbonyl and 1.3 grams per gallon of molybdenum as molybdenum tetradecanoate. v

The MnzMo atomic ratio of this fuel is about 1 110.5.

Example 21 Example 22 To base gasoline A is added 2.2 grams per gallon of manganese as (2-ethylhexylcyclopentadienyl)manganese tricarbonyl and 0.24 grams per gallon of molybdenum as molybdenum 4-methylbenzoate.

The MnzMo atomic ratio of this fuel is about 1:0.06.

Example 23 To a base gasoline containing 100 percent aromatic hydrocarbons is added 2.0 grams per gallon of manganese as cyclopentadienylmanganese tricarbonyl and 1.4 grams per gallon of molybdenum as the molybdenum salt of tall oil fatty acids.

The MnzMo atomic ratio of this fuel is about 1:0.4.

The small amount of organic molybdenum compound added to an organomanganese containing gasoline fuel significantly reduces spark plug fouling caused by deposit formation on the plug ignition surfaces. The activity of the organic molybdenum compounds as spark plug anti-foulants was detennined in an actual engine test. The engine used was a single cylinder spark ignition engine. The test cycle used was to run the cngine on the test fuel for 30 minutes with the throttle opened from to 100 percent at 1,200 RPM; the engine was then allowed to idle for sixty (60) seconds at 750 RPM. This cycle was repeated automatically until the engine stalled due to spark plug failure. The time to stall was recorded as Time to Failure."

Following are the results of a series of spark plug fouling tests run according to the test procedure set out above.

TABLE II Molybdenum Compounds As Spark Plug Antifoulants Test Mn Mo Time to No. Fuel Composition g/gal g/gal Failure hr.

1 lsooctane Mn antiknock 2.0 0 17.0 2 Example 1 2.0 0.25 32.4 3 Example 2 2.0 0.50 63.8

Mn as (methylcyclopentadienyl)manganese tricarbonyl Mo as Nuodex molybdenum naphthenate The data in Table II clearly illustrate the effectiveness of the molybdenum additives as spark plug antifoulants. The fuel composition (test 1) containing only the manganese primary antiknock caused spark plug failure after 17 hours. The addition of 0.25 g/gal. of Mo as molybdenum naphthenate increased time to failure up to 32.4 hours, a percent improvement in spark plug life; and 0.50 g/gal. of Mo as the naphthenate increased the time to failure to 63.8 hours, a 270 percent improvement in spark plug life.

Similar improvement in spark plug life is obtained when other organic molybdenum compounds, as disclosed herein, are added to gasoline fuels containing an organomanganese antiknock.

The present invention is embodied in (1) fuel compositions comprising a major portion of gasoline hydrocarbon, substantially free of tetrahydrocarbyl lead compounds, an anti-knock amount of an organomanganese compound and a spark plug antifoulant amount of an organic molybdenum compound, (2) concentrates containing the organomanganese compound and the organic molybdenum compound and (3) an improved method of operating a spark ignition engine. These embodiments have been described above.

With regard to the additive concentrates and to facilitate handling, these concentrates can be diluted with or dispersed in suitable gasoline compatible diluents, an expedient recognized in the art. Examples of suitable diluents or dispersants are C -C hydrocarbons, C C monoalkanols, combinations of these diluents and the like. These diluents may constitute from to 90 percent by weight of the concentrate.

The invention is claimed as follows.

1. A gasoline additive concentrate containing a mixture consisting essentially of cyclopentadienyl manganese tricarbonyl antiknock compound wherein said cyclopentadienyl group has up to l3 carbon atoms, and organic molybdenum compound selected from the group consisting of l. molybdenum chelate 2. molybdenum salts of a. phenol and C -C alkyl substituted phenols b. phosphoric acids having the formula it Xl lt X -l .x

where X, X, X and X are independently selected from O and S and R and R, are independently selected from hydrocarbon alkyl and aryl groups having from 1 to about 30 carbon atoms c. hydrocarbon carboxylic acids having from 5 to about 24 carbon atoms, and

d. naphthenic acids, such that the atomic ratio of manganesezmolybdenum is from about 1:1 to about l:0.05.

2. The additive concentrate of claim 1 wherein said molybdenum compound is molybdenum chelate.

3. The additive concentrate of claim 1 wherein said molybdenum compound is molybdenum salt of said phenol or alkyl substituted phenol.

4. The additive concentrate of claim 1 wherein said molybdenum compound is salt of said phosphoric acid.

5. The additive concentrate of claim 1 wherein said molybdenum compound is salt of said hydrocarbon carboxylic acid.

6. The additive concentrate of claim 1 wherein said molybdenum compound is a salt of said naphthenic acid.

7. The additive concentrate of claim 1 wherein said molybdenum compound is molybdenum naphthenate.

8. The additive concentrate of claim 1 wherein said manganese tricarbonyl is (methylcyclopentadienyl)- manganese tricarbonyl.

9. The additive concentrate of claim 7 wherein said manganese tricarbonyl is (methylcyclopentadienyl)- manganese tricarbonyl.

10. The additive concentrate of claim 1 wherein said atomic ratio is from about l:0.l4 to about 1:007.

11. The additive concentrate of claim 10 wherein said manganese tricarbonyl is (methylcyclopentadienyl)manganese tricarbonyl.

12. The additive concentrate of claim 11 wherein said molybdenum compound is said molybdenum salt.

13. The additive concentrate of claim 12 wherein said molybdenum compound is molybdenum naphthenate.

i t t I t 

2. The additive concentrate of claim 1 wherein said molybdenum compound is molybdenum chelate.
 2. molybdenum salts of a. phenol and C1-C18 alkyl substituted phenols b. phosphoric acids having the formula
 3. The additive concentrate of claim 1 wherein said molybdenum compound is molybdenum salt of said phenol or alkyl substituted phenol.
 4. The additive concentrate oF claim 1 wherein said molybdenum compound is salt of said phosphoric acid.
 5. The additive concentrate of claim 1 wherein said molybdenum compound is salt of said hydrocarbon carboxylic acid.
 6. The additive concentrate of claim 1 wherein said molybdenum compound is a salt of said naphthenic acid.
 7. The additive concentrate of claim 1 wherein said molybdenum compound is molybdenum naphthenate.
 8. The additive concentrate of claim 1 wherein said manganese tricarbonyl is (methylcyclopentadienyl)manganese tricarbonyl.
 9. The additive concentrate of claim 7 wherein said manganese tricarbonyl is (methylcyclopentadienyl)manganese tricarbonyl.
 10. The additive concentrate of claim 1 wherein said atomic ratio is from about 1:0.14 to about 1:0.07.
 11. The additive concentrate of claim 10 wherein said manganese tricarbonyl is (methylcyclopentadienyl)manganese tricarbonyl.
 12. The additive concentrate of claim 11 wherein said molybdenum compound is said molybdenum salt.
 13. The additive concentrate of claim 12 wherein said molybdenum compound is molybdenum naphthenate. 